I've just had a look at the forum on Her Interactive.
In response to a question from a fan as to whether there is going to be another ND the answer was, and I quote, "we are in development". It goes on to say that they are not in a position to release details at the moment. The date of the reply was earlier this month.

Does Gameboomers have any intel on this?

I don't want to raise any false hopes but i got a bit excited about this.

They have been saying that there has been a game in development for quite some time now, so there has been some speculation. We discussed it here on GameBoomers last year.

More here:

Seven Keys

Otherwise, no concrete announcement and nothing known for sure.

Thanks Marian, I missed that thread entirely.

So it's just one of those that happens if it happens. False alarm! I do hope they'll manage to release it in due course though.

It may or may not be a false alarm. We will just have to wait and see.